1. Field of the Invention
The present invention relates to the automatic control of trains, and in particular to positive train control systems and methodologies that provide enhanced safety by controlling the braking of a train including generating braking signals or requests that are provided to a train engineer and/or that automatically cause a brake application to occur.
2. Description of the Related Art
Positive train control (PTC) refers to various technologies that are used to monitor and control the movements of trains, such as passenger and freight trains, to provide increased safety. In PTC systems, the train receives information about its location, including maximum speed limits, and where it is allowed to safely travel. Equipment on-board the train then enforces these limits to prevent unsafe movement. In particular, PTC systems employ sophisticated braking algorithms designed to review speeds, track conditions, and vehicle locations and automatically slow a train or bring a train to a safe stop (by alerting the crew and/or automatically causing an emergency stop of the train) if the train encounters a condition (such as the engineer not paying attention to a signal or a switch not being fully engaged) that could lead to an accident. A typical PTC system consists of equipment provided on the train, equipment provided in a centralized control center, equipment provided on the rail wayside, and a wireless communication system that allows for wireless communications between the elements just identified.
While many known PTC systems and technologies have proven to be effective in certain situations, there is room for improvement in the field of positive train control, and in particular braking algorithms and related control functions.